Racked coils; because of tension or wobble, or something else?

[GlennW]

I wound a couple of coils yesterday and they both have the same problem, they're racked. Is this because of a slight wobble in the winder or because of a variation in tension, or something else? Thanks.

[Stan H]

Your winder's mounting plate is not at a perfect 90 degree angle to the shaft. I sometimes use a business card shim.

[GlennW]

Thanks, Stan. I thought that was it, but since I wound two coils without breaking the wire I also suspected tension. I'll fix it before I wind any more.